Use of sodium bisulfite in an improved process for the treatment of cellulose textile materials with carbamate finishing agents and sulfurous acid

ABSTRACT

An improved relationship of the strength to wrinkle recovery properties of cellulose-containing fabrics finished with methylol carbamate agents and sulfurous acid is obtained by inclusion of about 0.3-1 percent of sodium bisulfite in the treatment bath.

States Patent [191 Reid et al.

[451 Dec. 17, 1974 [75] Inventors: John D. Reid; Robert M. Reinhardt,both of New Orleans; Russell M. H. Kullman; Norton A. Cashen, both ofMetairie, all of La.

[73] Assignee: The United States of America as representedby theSecretary of Agriculture, Washington, DC.

[22] Filed: Dec. 13, 1972 [21] Appl. No.: 314,651

[52] U.S. Cl 8/187, 8/DIG. l1, ll7/l39.4, 252/8.8

[51] Int. Cl D06p 1/00 [58] Field of Search 8/181, 187, DIG. ll;252/8.6, 8.8; ll7/139.4

[56] References Cited UNITED STATES PATENTS 3,776,692 l2/l973 Franklinet al. 8/187 X Primary Examiner-Stephen J. Lechert, .Ir..

[ I ABSTRACT An improved relationship'of the strength to wrinklerecovery properties of cellulose-containing fabrics finished withmethylol carbamate agents and sulfurous acid is obtained by inclusion ofabout 0.31 percent of sodium bisulfite in the treatment bath.

6 Claims, No Drawings USE OF SODIUM BISULFITE IN AN IMPROVED PROCESS FORTHE TREATMENT OF CELLULOSE TEXTILE MATERIALS WITH CARBAMATE FINISHINGAGENTS AND SULFUROUS ACID A non-exclusive, irrevocable, royalty-freelicense in the invention herein described, throughout the world for allpurposes of the United States Government, with the power to grantsublicenses for such purposes, is hereby granted to the Government ofthe United States of America.

This invention relates to an improvement process for obtaining finishedfabrics which have higher strength to wrinkle recovery relationship thanthat normally encountered in fabrics which have been treated for durablepress properties with a methylol carbamate and sulfurous acid.Specifically, this invention relates to the addition of small quantitiesof sodium bisulfite to treatment formulations containing a methylolcarbamate agent and sulfurous acid so that fabrics treated with saidformulations for improved wrinkle recovery will benefit by having higherstrength at a-given level of wrinkle recovery than fabrics similarlytreated but without sodium bisulfite.

Recently developed processes for producing durable press fabrics haveutilized low temperature curing with strong acid catalysts. However,careful control of treatment conditions is necessary to avoid undue lossof strength in these finished fabrics. In the treatment ofcellulose-containing fabrics, sulfurous acid has been shown to be aneffective acid for catalysis to promote reaction between N-me'thyloltype crosslinking agents and the cellulose. Materials processed withformulations containing strong acids, such as sulfurous acid, andN-methylol agents frequently have low strength when high levels ofwrinkle resistance (as measured by wrinkle recovery angles) areachieved. Obviously, this strength to wrinkle recovery relationship isimportant to the textile manufacturer who must employ fabric withsuitable strength for use in durable press materials, particularlydurable press wearing apparel.

in the prior art, sodium bisulfite and other compounds capable offorming HSO ions in solution have been employed for odor control infinished textiles. ln US. Pat. No. 2,870,041,.it is suggested thata'reaction occurs between the H80 ions, as supplied by Nal-I- SO:;, andthe aldehyde of the treatment solution to overcome undesirable odors.The specification also suggests that the resultant product is stableonly in the presence of mildly acidic or basic reagents. They furthersuggest that the H50; ions furnished may funcpress fabrics. Each processhas its inherent advantage but most processes suffer from an economical.disadvantage or sacrifice of wrinkle recovery in achieving greaterstrength in the finished fabric. A simple process to achieve a betterstrength to wrinkle recovery relationship in textiles has been needed,particularly in the area of N-methylol carbamate finishing agents wheninexpensive, strong acids, such as sulfurous acid, are employed ascatalysts in the treatment formulations.

It is the principal object of the present invention to provide such aprocess.

We have found that contrary to suggestions in the patent literature,sodium bisulfite will not act as a catalyst for the treatment ofcellulose textile materials with N- methylol carbamate agents to produceimproved wrinkle recovery. Surprisingly, however, we have discoveredthat the use of small quantities of sodium bisulfite in conjunction withsulfurous acid in the treatment of cellulose textile materials withcarbamate agents provides a finished fabric with greater strength at agiven level of wrinkle recovery'than when sodium bisulfiteis curing theimpregnated fabric. The fabric may be cured tion as a catalyst forcuring of the finishing agent. Conultimate user of the textile product.The literature is far too voluminous to cite the many works ofresearchers who have attempted to find new and improved processes toachieve fabrics with durable press properties and better strength. Inthe prior art, such broad areas of processing as tension mercerization,polymer additives, low cure temperatures, and even certain salt ad-'ditives, have been investigated in seeking better strength to wrinkleresistance relationships in durable N-Methylol carbamate finishingagents that can be used in the formulations and process of thisinvention include formaldehyde adducts of alkyl carbamates, alkoxyalkylcarbamates, hydroxyalkyl carbamates and the like. N-Acetoxymethyl andN-alkoxymethyl derivatives v of these carbamates also can be used. Theamount of agent used may vary fromabout 3 to about 20 percent, byweight, based upon the weight of the treatment bath. About from 10 to 15percent of the N-methylol carbamate agent, or the equivalent ofN-alkoxymethyl or N-acetoxymethyl carbamate agent is preferred.

Small quantities of sodium bisulfite are effective in the process ofthis invention. The concentration of sodium bisulfite used may vary fromabout 0.1 toabout 1 part per parts, by weight, of the treatmentformulation. A preferred range is from about 0.3 to 1 part per 100 partsof treatment formulation.

Temperatures that may be used to cure the impregnated fabric are fromabout 80 to C, correlated respectively with timesfrom about 4 minutes toabout 2 minutes, the preferred temperatures being about In summary, theuse of small quantities of sodium bi sulfite with a carbamate finishingagent and sulfurous acid in the treatment of cellulose-containingtextile materials has advantages over the use of the carbamate agent andsulfurous acid in the absence of the said salt.

By adding sodium bisulfite to the treatment formulation, a wider rangeof curing temperatures may be used to achieve a better strength towrinkle recovery relationship in the treated textile material than thatobtained by treatment with formulations containing a methylol carbamatefinishing agent and sulfurous acid. The sodium bisulfite may be employedin finishing processes using pad-dry-cure steps and in the mild curefinishing process.

The following examples are provided for illustration and in no way areintended to limit the scope and spirit of the invention. Numerouschanges and modifications to the detailed and specific examples will bereadily apparent to those skilled in the art. I

In the descriptions of solution formulations given in these examples,all parts are by weight unless otherwise specified.

EXAMPLE 1 A formulation (100 parts) was prepared containing parts ofdimethylol methyl carbamate, 4 parts of sodium bisulfite, and 86 partsof water. A cotton printcloth, Sample A, was impregnated with theformulation and passed through squeeze rolls to obtain about 90 percentwet pickup of the formulations on the fabric. The fabric was dried at60C for 7 minutes and cured at 120C for 3 minutes. Residual chemicals inthe fabric were removed by washing and the fabric was tumble dried.

in another treatment, an aqueous formulation (100 parts) was prepared tocontain 10 parts of dimethylol methyl carbamate, 4 parts of sodiumbisulfite, and 0.1 parts of sulfurous acid. A'portion of cottonprintcloth was treated (Sample 13) as was Sample A.

The treated fabrics and an untreated control (Sample C) were tested forwrinkle recovery by the method of the American Society for Testing andMaterials: Test Dl424-56T and analyzed for nitrogen content by theKjeldahl method. Results are listed in Table 1.

TABLE I SAMPLE NlTROGEN WRINKLE RECOVERY ANGLE lDENTlFl- CONl'ENT,%(Warp +'Filling), deg.

CATlON Sample A 0.02 200 Sample B 0.03 201 Sample C 0.02 201 Thisconclusively illustrates that sodium bisulfite does not act as acatalyst for the reaction of a methylol carbamate. finishing agent withcotton. Furthermore, if a relatively large quantity of sodium bisulfiteis used in conjunction with sulfurous acid (Sample B) the catalyticactivity produced by the'latter is depressed so that the desiredreaction between the finishing agent and cellulose does not occur andthere is no improvement in wrinkle recovery.

EXAMPLE 2 An aqueous formulation (100 parts) was prepared to contain 10parts of dimethylol methyl carbamate, 0.1

' dried.

Another aqueous. formulation (100 parts) was prepared to contain 10parts of dimethylol methyl carbamate, and 0.1 part of sulfurous acid butwith no sodium bisulfite present. Swatches of cotton printcloth werethen treated as above with this formulation.

All of the treated fabrics were tested for wrinkle recovery angles andfor breaking strength (according to the procedure of the AmericanSociety for Testing and Materials: Method D1682-64).

, The values of strength were plotted graphically as a function ofwrinkle recovery for each treatment. From these plotted prints, a curvewas drawn for the series of treatments with sodium bisulfite and anothercurve was drawn for those without sodium bisulfite. A comparison wasmade of breaking strengths for each type of treatment (treatmentformulations with sodium bisullite and treatment formulations withoutsodium'bisulfite) at various levels of wrinkle recovery. These resultslearn that the strength improvement was greatest at the higher levels ofwrinkle resistance.

EXAMPLE 3 Three aqueous formulations parts each) were prepared, eachcontaining '10 parts of dimethylol methyl carbamate,0.l part ofsulfurous acid, and 0.0 0.3, and 0.5 part of sodium bisulfite,respective. Cotton printcloth was treated with these formulations as inExample 1. Durable press appearance after tumble dry- I ing, asdetermined by the procedure of the American Association of TextileChemists and Colorists, AATCC Test Method 124-1967 (AATCC TechnicalManual, Volume 46, pages 177-8, 1970) and breaking strength of fabricsare shown in Table 111.

From these results it is seen that 03-05 part of sodium bisulfite areeffective in giving strength improvement with high durable pressratings.

EXAMPLE 4 and wrinkle recovery angles. Results are given in Table IV.

TABLE IV NaHSO in Nitrogen Breaking Treatment Content Strength WrinkleRecovery Angle Formulation lbs. (Warp Filling), deg.

At the relatively low curing temperature of 100C, sodium bisulfite isobviously beneficial to the strength of the fabric finished withdimethylol methyl carbamate. lt is also evident that with 0.2 part ofsulfurous acid and 15 parts of dimethylol methyl carbamate there is noreduction in reaction efficiency, as exemplified by nitrogen content, inthe presence of sodium bisulfite.

EXAMPLE 5 Four aqueous formulations (100 parts each) were preparedcontaining parts of dimethylol methyl carbamate, 0.15 part of sulfurousacid and 0.0, 0.3, 0.5, and 1 part of sodium bisulfite, respectively.Swatches of cotton printcloth were impregnated with these formulationsand squeezed by rolls to obtain about 90 percent wet pickup of theformulation on the fabric. The fabrics were dried at 60C for 7 minutesand-cured at 140C for 3 minutes. Residual chemicals were removed bywashing and the fabrics were tumbled dried. Fabric properties are shownin Table V.

TABLE V Increase in NaHSO, in Breaking Strength with Wrinkle Recoveia/Treatment Strength NaHSO in Treat- Angle arp Formulation lbs. mentFormulation Filling), deg.

Thesignificant improvement in breaking strength with increased amountsof sodium bisulfite in these formulations is surprisingly large at thiscuring temperature of 140C. It is also surprising to find that there isno loss in wrinkle recovery angle along with the increase in strength.

We claim:

1. An improved process in the treatment of cellulosecontaining fabricswith a methylolated carbamatesulfurous acid formulation which processcomprises adding a minor amount of sodium bisulfite to said formulation,impregnating the cellulose-containing textile with said formulation andcuring the impregnated fabric to impart durable press properties withimproved strength-to-wrinkle recovery relationship tothe treated fabric.

2. The process of claim 1 wherein every 100 parts by weight of themethylolated carbamate-sulfurous acid formulation contains about from0.3 to 10 part by weight of sodium bisulfite.

3. The processof claim 1 wherein the methylolated carbamate of themethylolated carbamate-sulfurous acid formulation is dimethylol'methylcarbamate.

4. A process for treating cellulose-containing textiles to impartdurable press properties with an improved strength-to-wrinkle recoveryrelationship, the process comprising:

a methylolated carbamate-sulfurous acid formulation so that in every 100parts by weight of the formulation there is about from 10 to parts byweight of a methylolated carbamate, about from 0.1 to 0.2 part by weightof sulfurous acid, and about from 0.3 to 1 part by weight of sodiumbisulfite;

b. impregnating a cellulose-containing textile with a formulation from(a); and

' c. curing the wet impregnated textile for about from 2 to 4 minutes atabout 100 C. and washing and drying the cured textile.

5. Aprocess for treating cellulose-containing textiles -0 to impartdurable press properties with an improved strength-to-wrinkle recoveryrelationship, the process comprising:

a. adding a sufficient quantity of sodium bisulfite to a methylolatedcarbamate-sulfurous acidformulation so that in every 100 parts by weightof the formulation there is about from 10 to 15 parts by weight of amethylolated carbamate, about from 0.1 to 0.2 parts by weight ofsulfurous acid, and about from.0.3 to 1 part by weight of sodiumbisulfite; b. impregnating a cellulose-containing textile with aformulation from step (a); c. drying the wet impregnated textile forabout seven minutes at about from C. and d. curing the dry impregnatedtextile for about 3 minutes at about from to C. and washing and.

drying the cured textile.

wrinkle recovery relationship with respect to a control fabric treatedwith an identical formulation to that used in claim 5 except for theomission of sodium bisulfite. i i

1. AN IMPROVED PROCESS IN THE TREATMENT OF CELLULOSECONTAINING FABRICSWITH A METHYLOLATED CARBAMATE-SULFUROUS ACID FORMULATION WHICH PROCESSCOMPRISES ADDING A MINOR AMOUNT OF SODIUM BISULFITE TO SAID FORMULATION,IMPREGNATING THE CELLULOSE-CONTAINING TEXTILE WITH SAID FORMULATION ANDCURING THE IMPREGNATED FABRIC TO IMPART DURABLE PRESS PROPERTIES WITHIMPROVED STRENGTH-TO-WRINKLE RECOVERY RELATIONSHIP TO THE TREATEDFABRIC.
 2. The process of claim 1 wherein every 100 parts by weight ofthe methylolated carbamate-sulfurous acid formulation contains aboutfrom 0.3 to 1.0 part by weight of sodium bisulfite.
 3. The process ofclaim 1 wherein the methylolated carbamate of the methylolatedcarbamate-sulfurous acid formulation is dimethylol methyl carbamate. 4.A process for treating cellulose-containing textiles to impart durablepress properties with an improved strength-to-wrinkle recoveryrelationship, the process comprising: a. adding a sufficient quantity ofsodium bisulfite to a methylolated carbamate-sulfurous acid formulationso that in every 100 parts by weight of the formulation there is aboutfrom 10 to 15 parts by weight of a methylolated carbamate, about from0.1 to 0.2 part by weight of sulfurous acid, and about from 0.3 to 1part by weight of sodium bisulfite; b. impregnating acellulose-containing textile with a formulation from (a); and c. curingthe wet impregnated textile for about from 2 to 4 minutes at about 100*C. and washing and drying the cured textile.
 5. A process for treatingcellulose-containing textiles to impart durable press properties with animproved strength-to-wrinkle recovery relationship, the processcomprising: a. adding a sufficient quantity of sodium bisulfite to amethylolated carbamate-sulfurous acid formulation so that in every 100parts by weight of the formulation there is about from 10 to 15 parts byweight of a methylolated carbamate, about from 0.1 to 0.2 parts byweight of sulfurous acid, and about from 0.3 to 1 part by weight ofsodium bisulfite; b. impregnating a cellulose-containing textile with aformulation from step (a); c. drying the wet impregnated textile forabout seven minutes at about from 60* C. and d. curing the dryimpregnated textile for about 3 minutes at about from 80* to 160* C. andwashing and drying the cured textile.
 6. A cellulosic fabric prepared bythe process of claim 5, characterized by an improved strength-to-wrinklerecovery relationship with respect tO a control fabric treated with anidentical formulation to that used in claim 5 except for the omission ofsodium bisulfite.